• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.230-233
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• 1998

Acetic acid producing bacteria were isolated from deastringent persimmon vinegar and the major bacterium was identified using morphological and biochemical tests. Acetobacter sp. AH-1 was motile, gram negative rod with catalase positive and oxidase negative. The strain can grow up to 5 % ethanol and 2% NaCl as well as 25% glucose. Optimum temperature and pH for growth were 3$0^{\circ}C$ and 5.0, respectively. Volatile constituents of persimmon vinegar were analyzed by purge and trap sampling . Acetic acid adn alcohol were the largest volatile compounds quantitiatively in persimmon vinegar. Among alcohols, 20methyl-1-propanol, isoamyl alcohol and amyl alcohol were detected. Isovaleradehyde and benzaldehyde for aldehyde, isoamyl acteate, ethyl formate, propyl aceetate, and ethyl acetate for esters were likely to contribute to persimmon vivegar flavor.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.533-536
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• 2006

재생 가능한 자원인 동 식물성 기름으로부터 제조되는 수소용 연료 바이오디젤은 낮은 대기오염 배출과 $CO_2$ Neutral 특성으로 환경 친화적인 연료로 인정을 받으며 전 세계적으로 그 생산량이 급격히 증가하고 있다. 바이오디젤 생산 기술에는 직접이용법, 마이크로 에멀젼법, 열분해법, 에스테르화법, 초임계 메탄올 이용 생산법 등이 있으며 현재의 대부분의 상용 공정은 전이에스테르화법에 근거하고 있다. 이 공정은 크게 나누어 원료 유지 물질의 전처리 단계, 촉매를 사용하여 알콜과 에스테르화시키는 단계, 그리고 생성된 바이오디젤/글리세린의 분리와 정제 단계로 이루어지며 각 단계의 세부기술은 바이오디젤 생산비에 직접적인 영향을 미친다. 본 연구에서는 대두 원유의 전처리 반응, 전처리된 대두원유의 전이에스테르화 반응, 그리고 분리 및 정제 공정의 운전 변수들의 영향에 대한 연구결과와 본 연구를 통해 확립된 생산 공정으로 생산한 연료 grade의 바이오디젤 연료 물성 평가하였다.

• Journal of the Korean Applied Science and Technology
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• v.3 no.1
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• pp.39-42
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• 1986

The antioxidant activity of petroleum ether extract of Panax ginseng roots in the oxidation of mixed methyl esters of unsaturated fatty acids(MEUFA) was investigated in vitro. The petroleum ether extract of panax ginseng roots showed the antioxidant activity and inhibited the weight gain in the autoxidation of MEUFA. And the induction periods in the autoxidation of MEUFA were related to te addition concentrations of petroleum ether extact. The antioxidant effect of petroleum ether extract on the autoxidation of MEUFA was caused by the protective formation of lipid peroxides and carbonyl compounds. From the results obtained, it was confirmed that petroleum ether extract of panax ginseng roots contained antioxidant substances.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.494-501
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• 1993

The volatile flavor components of traditional and commercial kochujang were collected by simultaneous steam distillation-extraction (SDE) method. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC/MS). Tested kochujang included Sunchang kochujang prepared with glutinous rice, Boeun kochujang prepared with barley, Sachun kochujang prepared with wheat and commercial kochujang. One hundred and twelve volatile flavor components which included 30 esters, 15 alcohols, 14 aldehydes, 13 acids, 9 ketones, 7 alkenes, 6 phenols, 3 alkanes, 3 pyrazines, 2 benzenes and 2 furans were identified. The major volatile compounds in traditional and commercial kochujang were 2-methyl propanal and ethanol, which represented $21{\sim}36%\;and\;2{\sim}44%$ of total GC peak area, respectively.

• Journal of Food Hygiene and Safety
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• v.9 no.2
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• pp.89-94
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• 1994

A simple, safe, and sensitive gas chromatographic method using packed column and electron capture detector to analyze 2, 4-D herbicide in imported lemon, grapefruit, and orange was described and its usefulness evaluated. In this scheme of analysis the acid herbicide was converted into its alkyl esters by an one-step reaction prior to analysis. The herbicide in the fruits was extracted with ethyl acetate and partitioned against dichloromethane for purification, and the extracts finished partitioning were derivatized with alcohol, using sulfuric acid as a catalyst to form the corresponding alkyl derivatives. The analytical scheme studiedwas found to be applicable for the herbicide in the fruits without a column clean-up procedure. The mean recoveries of the herbicide for lemon samples fortified at 0.1 mg/kg and 1.0 mg/kg were 93% and 95%, respectively. The detection limit was 0.5 $\mu\textrm{g}$/kg for 2.4-D methyl ester.

• Proceedings of the Culinary Society of Korean Academy Conference
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• 2005.10a
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• pp.61-86
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• 2005

Kimchi power made by kimchi fermentation and freeze-drying was added to Western foods of sauce, soup, pizza, cracker and bread. Flavor qualities of the processed fusionfoods were evaluated by analyzing volatile compounds and sensory evaluation. The optimum condition of kimchi fermented for the best flavor quality of freeze-drying was the ranges of pH4.0${\sim}$pH4.7 and acidity 0.5${\sim}$0.8. The number of volatile compounds identified from extracts of the freeze-dried kimchi powder was 24, which contained 7 alcohols, 5 esters, 5 acids, 3 sulfur-containing compounds, 2 aldehydes, 1 oxygen-containing and 1 other. Among the identified compounds, the most abundant compound was eugenol(39.40%), followed as the order of dodecanoic acid(4.91%), acetic acid(1.70%), methyl 2-propenyl disulfide(1.52%), hexanal(1.51%) and 2-pentylfuran(1.18%). These compounds affected the flavor quality of kimchi powder.

• Preventive Nutrition and Food Science
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• v.11 no.3
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• pp.253-256
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• 2006

The purpose of this study was to develop a gas chromatographic (GC) method to analyze fatty acids in milk fat with a single injection. The single-injection GC method we developed for analyzing fatty acid composition can separate a wide range of fatty acid methyl esters from butyric acid to docosahexaenoic acid. It separated 6 isomers of 18:1 (cis-6, cis-9, cis-11, trans-6, trans-9 and trans-11), 4 isomers of 18:2 (cis-9-cis-12, trans-9-trans-12, cis-9-trans-12 and trans-9-cis-12), and 4 isomers of conjugated 18:2 (cis-9- trans-11, trans-9-cis-11, cis-10-trans-12 and trans-10-cis-12).

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.311-318
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• 1991

Corneal permeability of various n-alkyl p-hydroxybenzoates (parabens) was studied in vitro using excised rabbit corneas, and the effect of lipophilicity of parabens on the corneal permeability was also investigated. Permeability coefficients were obtained from the least-square linear regression after the steady state had been reached. Lipophilicity of parabens was calculated by distribution coefficients determined in octanol-S | $12{\phi}{\parallel}$) rensen's buffer solution (pH 5.0). The relationship between lipophilicity and corneal permeability of parabens was not linear, but the optimum lipophilicity for the maximum permeation was found. The influence of tween 80 on corneal permeability of methyl and butylparaben was not significant.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.65-68
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• 2003

The paper discusses the use of stable emulsion, prepared by membrane emulsification technology, to improve the enantiocatalytic performance of immobilised lipase in multiphasic membrane reactors. The production of optical pure (S)-naproxen from racemic naproxen methyl ester has been used as model reaction system. The enzyme was immobilised in the sponge layer (shell side) of capillary polyamide membrane with 50 kDa cut-off, The O/W emulsion, containing the substrate in the organic dispersed phase, was fed to the enzyme membrane reactor from shell-to-lumen. The results evidenced that lipase maintained stable activity during all the operation time (more than 250 hours), showing an enantiomeric excess (96 $\pm$2%) comparable to the free enzyme (98 $\pm$ 1%) and much higher compared to similar lipase-loaded membrane reactors used in two-separate phase systems (90%). The study showed that immobilised enzymes can achieve high stability as well as high catalytic activity and enantioselectivity.

• Bulletin of the Korean Chemical Society
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• v.2 no.3
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• pp.105-112
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• 1981

Various $3{\alpha}$, $5{\alpha}$-cyclocholestan-6${\beta}-yl$ ethers were synthesized from solvolysis reactions of cholesteryl tosylate. ${3\alpha}$, $5{\alpha}$-Cyclocholestan-6${\beta}-yl$ sulfides were the sole products when cholesteryl tosylate was solvolyzed in thiol solvents. Diol solvolysis products were derivatized to aromatic esters, and nuclear magnetic resonance spectroscopic method was used to show that aromatic rings can approach C-18 methyl group and the side chain.